Driving mechanism

ABSTRACT

A driving mechanism is provided, including a polygonal base unit, a holder, a first driving assembly, a sensing magnet, and a magnetic field sensor. The polygonal base unit includes a substrate and a circuit board disposed on the substrate. The holder is movably connected to the base unit, wherein the holder is configured to hold an optical element that defines an optical axis. The first driving assembly is configured to drive the holder to move relative to the base unit. The sensing magnet is disposed on the holder. The magnetic field sensor is configured to detect the sensing magnet, wherein the magnetic field sensor is accommodated in a recess of the substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/257,454, filed Jan. 25, 2019, which claimspriorities of U.S. Provisional Application No. 62/621,967, filed on Jan.25, 2018, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a driving mechanism, and more particularly to adriving mechanism that can move an optical element.

Description of the Related Art

In existing dual-lens camera systems, two lens driving modules areusually arranged close to each other, and as a result, magneticinterference between the magnets of the two lens driving modules islikely to occur, causing the focus speed and accuracy of the lenses tobe adversely affected. Therefore, what is needed is a dual-lens camerasystem that can prevent the magnetic interference between the two lensdriving modules.

BRIEF SUMMARY OF THE INVENTION

In view of the aforementioned problems, an object of the invention is toprovide a driving mechanism that includes a polygonal base unit, aholder, a first driving assembly, a sensing magnet, and a magnetic fieldsensor. The polygonal base unit includes a substrate and a circuit boarddisposed on the substrate. The holder is movably connected to the baseunit, wherein the holder is configured to hold an optical element thatdefines an optical axis. The first driving assembly is configured todrive the holder to move relative to the base unit. The sensing magnetis disposed on the holder. The magnetic field sensor is configured todetect the sensing magnet, wherein the magnetic field sensor isaccommodated in a recess of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is an exploded diagram showing a driving mechanism 1 inaccordance with an embodiment of the application.

FIG. 2 is a schematic diagram showing the driving mechanism 1 of FIG. 1after assembly.

FIG. 3 is a cross-sectional view taken along line A1-A1 in FIG. 2.

FIG. 4 is a cross-sectional view taken along line A2-A12 in FIG. 2.

FIG. 5 is a schematic diagram showing the driving mechanism 1 of FIG. 2with the housing 10, the frame 50, the upper spring S1, the lower springS2, and the resilient member W removed therefrom.

FIG. 6 is a schematic diagram showing a cross-sectional view of adriving mechanism 1 in accordance with another embodiment of theapplication.

FIG. 7 is a schematic diagram showing a driving module in accordancewith another embodiment of the application.

FIG. 8 is a schematic diagram showing some components of a drivingmechanism in accordance with another embodiment of the application.

FIG. 9 is a schematic diagram showing some components of a drivingmechanism in accordance with another embodiment of the application.

FIG. 10 is a schematic diagram showing a driving module in accordancewith another embodiment of the application.

FIG. 11 is a schematic diagram showing a driving module in accordancewith another embodiment of the application.

FIGS. 12 and 13 are exploded diagrams showing a base unit in accordancewith another embodiment of the application.

DETAILED DESCRIPTION OF THE INVENTION

The making and using of the embodiments of a driving mechanism arediscussed in detail below. It should be appreciated, however, that theembodiments provide many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the embodiments, and do not limit the scope of the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. It should be appreciated thateach term, which is defined in a commonly used dictionary, should beinterpreted as having a meaning conforming to the relative skills andthe background or the context of the present disclosure, and should notbe interpreted in an idealized or overly formal manner unless definedotherwise.

FIG. 1 is an exploded diagram showing a driving mechanism 1 inaccordance with an embodiment of the application. FIG. 2 is a schematicdiagram showing the driving mechanism 1 of FIG. 1 after assembly. FIG. 3is a cross-sectional view taken along line A1-A1 in FIG. 2. FIG. 4 is across-sectional view taken along line A2-A12 in FIG. 2. FIG. 5 is aschematic diagram showing the driving mechanism 1 of FIG. 2 with thehousing 10, the frame 50, the upper spring S1, the lower spring S2, andthe resilient member W removed therefrom.

Referring to FIGS. 1-5, the driving mechanism 1 in this embodiment maybe a voice coil motor (VCM) which can be disposed in a camera of a cellphone for driving an optical element to move. The driving mechanism 1primarily comprises a housing 10, a substrate 20, a circuit board 30, aholder 40, a frame 50, at least an upper spring S1, and at least a lowerspring S2.

The holder 40 connects to the frame 50 via the upper and lower springsS1 and S2. The optical element such as an optical lens can be disposedin the holder 40, and two coils C1 are disposed on opposite sides of theholder 40.

The housing 10 is affixed to the substrate 20, and the frame 50 has arectangular hollow structure movably connected to the substrate 20 byfour resilient members W (e.g. thin metal rods). In this embodiment, thesubstrate 20 and the circuit board 30 constitute a polygonal base unitof the driving mechanism 1.

As shown in FIGS. 1-3 and 5, two magnets M1 are disposed on two oppositesides of the frame 50, parallel to the X axis and adjacent to the coilsC1. When electrical currents are applied to the coils C1,electromagnetic forces can be produced by the magnets M1 and the coilsC1 for driving the holder 40 and the optical element therein to moverelative to the frame 50 along the Z axis, so as to achieveauto-focusing of the camera.

Referring to FIGS. 1-2 and 4-5, a magnetic element M2 (e.g. magnet) isdisposed on a side of the frame 50, parallel to the Y axis and close toa first side 201 of the base unit. As shown in FIG. 4, another coil C2is embedded in the circuit board 30 and located corresponding to themagnetic element M2. Here, the magnetic element M2 and the coil C2constitute a driving assembly (first driving assembly) for driving theframe 50, the holder 40, and the optical element therein to moverelative along the X axis when an electrical current is applied to thecoil C2, so as to achieve Optical Image Stabilization (OIS) of thecamera.

FIG. 4 further shows a protrusion 41 formed on a side of the holder 40and close to a second side 202 of the base unit. Specifically, a sensingmagnet M3 is disposed in a cavity of the protrusion 41, and two magneticfield sensors HS (e.g. Hall sensors) are disposed on the bottom side ofthe circuit board 30 and accommodated in two cavities of the substrate20 for detecting the magnetic element M2 close to the first side 201 andthe sensing magnet M3 close to the second side 202, so that thedisplacement amount of the holder 40 relative to the base unit along theZ axis can be obtained. The two magnetic field sensors HS areelectrically connected to the circuit board 30, and when viewed in adirection parallel to an optical axis O of the optical element, therecess of the substrate 20 and the cavity of the holder 40 at leastpartially overlap.

In this embodiment, the polar direction of the sensing magnet M3 isparallel to the optical axis O, and the center of the magnetic fieldsensor HS is offset from the center of the sensing magnet M3 along ahorizontal direction (X direction). Therefore, the magnetic interferencebetween sensing magnet M3 and other components inside or outside thedriving mechanism 1 can be efficiently prevented. When viewed along theZ axis, the sensing magnet M3 may have a round, square, or rectangularshape. When the sensing magnet M3 has a longitudinal structure, alongitudinal axis of the sensing magnet M3 is parallel to the secondside 202 and the Y axis, so as to facilitate both miniaturization andstability of the driving mechanism 1.

It should be noted that the second side 202 of the base unit is parallelto the first side 201 of the base unit, and the optical axis O of theoptical element is located between the first and second sides 201 and202. Specifically, there is no driving assembly disposed on the secondside 202 of the base unit such as the coil C2 and the magnet M2 (firstdriving assembly) disclose above.

Furthermore, to balance the weight of the driving mechanism 1, a blockG1 is disposed on the frame 50. As shown in FIGS. 1 and 5, the drivingmechanism 1 in this embodiment comprises two blocks G1 and a metal sheetG2 connecting to the blocks G1, wherein the blocks G1 may be affixed toa side of the frame 50 and close to the second side 202 of the baseunit. Since the two blocks G1 can be connected to each other by themetal sheet G2, the protrusion 41 of the holder 40 can be positionedbetween the two blocks G1 after assembly. That is, when viewed along adirection parallel to the second side 202 (the Y axis), the blocks G1and the sensing magnet M3 at least partially overlap.

In some embodiments, the blocks G1 and the metal sheet G2 aremagnetically impermeable. When the holder 40 moves relative to the frame50 along a horizontal direction (the X axis) to a limit position, atleast one of the blocks G1 may contact and restrict the holder 40 in thelimit position.

FIG. 6 is a schematic diagram showing a cross-sectional view of adriving mechanism 1 in accordance with another embodiment of theapplication. As shown in FIG. 6, the holder 40 in this embodiment has anextending portion 42 overlapping with the first driving assembly (themagnetic element M2 or the coil C2) when viewed along the optical axisO.

To increase the electromagnetic force generated by the magnetic elementM2 or coil C2 along the X axis, the magnetic element M2 may define arectangular cross-section, wherein the width of the cross-section alongthe X axis is greater than the thickness of the cross-section long the Zaxis. Additionally, since the extending portion 42 is formed on a sideof the holder 40 above the magnetic element M2, the weight of thedriving mechanism 1 can be balanced, and the space inside the drivingmechanism 1 can be efficiently utilized, so as to facilitate bothminiaturization and stability of the driving mechanism 1.

FIG. 7 is a schematic diagram showing a driving module in accordancewith another embodiment of the application. The driving module in FIG. 7comprises four driving mechanisms 1 arranged in a 2×2 matrix. The fourdriving mechanisms 1 are different from the driving mechanism 1 of FIGS.1-5 in that each of the driving mechanisms 1 has only one pair of magnetM1 and coil C1 (second driving assembly) close to a third side 203 ofthe base unit. Specifically, there is no driving assembly (such as themagnet M1 and the coil C1) disposed close to a fourth side 204 of thebase unit, wherein the fourth side 204 is opposite to the third side203.

As shown in FIG. 7, since the four driving mechanisms 1 are spaced closeto each other, the driving assembly including large magnetic elements(such as the magnet M1 or the magnetic element M2) is prevented frombeing disposed close to the second and fourth sides 202 and 204 of thebase units of the four driving mechanisms 1, so that the magneticinterference between adjacent driving mechanisms 1 can be avoided, andrapid focusing and high positioning accuracy of the camera can beachieved. Here, the second and fourth sides 202 and 204 of the baseunits of the four driving mechanisms 1 are adjacent to each other.

FIG. 8 is a schematic diagram showing some components of a drivingmechanism in accordance with another embodiment of the application. FIG.8 is different from the driving mechanism 1 of FIGS. 1-5 in that thecenter of the magnetic field sensor HS, the protrusion 41 of the holder40, and the sensing magnet M3 therein are offset from the center of side202 of the base unit along the Y axis, as the central line L indicatesin FIG. 8.

As mentioned above, since the protrusion 41 of the holder 40 and thesensing magnet M3 efficiently occupy the space beside the central line Lof the second side 202, the considerable dimension of the drivingmechanism along the X axis owing to the protrusion 41 and the sensingmagnet M3 can be reduced, whereby miniaturization and balance of thedriving mechanism can be both achieved.

FIG. 9 is a schematic diagram showing some components of a drivingmechanism in accordance with another embodiment of the application. FIG.9 is different from FIG. 8 in that the center of the magnetic fieldsensor HS is located on a central line L of the second side 202 of thebase unit, and the protrusion 41 of the holder 40 and the sensing magnetM3 in the protrusion 41 are offset from the center of the side 202 ofthe base unit and the magnetic field sensor HS along the Y axis.

In this embodiment, though the sensing magnet M3 is slightly offset fromthe magnetic field sensor HS along the Y axis, the magnetic field sensorHS can still detect the sensing magnet M3 to obtain the displacementamount of holder 40 relative to the base unit along the Z axis. Sincethe protrusion 41 of the holder 40 and the sensing magnet M3 efficientlyoccupy the space beside the central line L of the second side 202,miniaturization and weight balance of the driving mechanism can still beachieved.

FIG. 10 is a schematic diagram showing a driving module in accordancewith another embodiment of the application. The driving module in FIG.10 comprises two driving mechanisms 1 as disclosed on FIG. 8 or FIG. 9,The two driving mechanisms 1 are arranged in a direction, wherein theprotrusions 41 of the holders 40 and the sensing magnets M3 in theprotrusions 41 are offset from the centers of the sides 202 of the twobase units, whereby miniaturization and weight balance of the mechanismcan be both achieved. Furthermore, since no driving assembly includinglarge magnet and coil is disposed close to the second sides 202 of thebase units, the magnetic interference between the two driving mechanisms1 can be efficiently prevented, whereby rapid focus and high positioningaccuracy of the camera can be achieved. Here, the second sides 202 ofthe base units of the two driving mechanisms 1 are adjacent to eachother.

FIG. 11 is a schematic diagram showing a driving module in accordancewith another embodiment of the application. The driving module in FIG.11 is different from FIG. 10 in that the second sides 202 of the baseunits of the two driving mechanisms 1 face in the same direction.

Similar to the embodiment of FIG. 10, no driving assembly includinglarge magnet and coil is disposed close to the second sides 202 of thetwo base units. Though the second side 202 of the base unit in a drivingmechanism 1 is close to the magnetic element M2 in the other drivingmechanism 1, serious magnetic interference between the two drivingmechanisms 1 can still be avoided. Thus, the flexibility of mechanismdesign can be greatly increased.

FIGS. 12 and 13 are exploded diagrams showing a base unit in accordancewith another embodiment of the application. The base unit of FIGS. 12and 13 comprises a substrate 20 and a circuit board 30, and it cansubstitute for the substrate 20 and the circuit board 30 (base unit) inFIG. 1.

As shown in FIG. 12, several magnetic field sensors HS are disposed onthe bottom side of the circuit board 30 to detect the magnet M1, themagnetic element M2, and the sensing magnet M3. Specifically, aplurality of first and second pads 21 and 22 are exposed to an innersurface of an opening of the substrate 20, and they can be electricallyconnected to an external circuit via the conductive pins P.

It should be noted that the first pads 21 are adjacent to each other,and the second pads 22 are adjacent to each other, wherein the first andsecond pads 21 and 22 are located on opposite sides of the opening forelectrically connecting to the first and second conductive portions 31and 32 which are exposed to the bottom of the circuit board 30. Thefirst and second conductive portions 31 can electrically connect to themagnetic field sensors HS via the electrical circuits inside the circuitboard.

As shown in FIG. 13, the substrate 20 forms at least a recess R forreceiving the magnetic field sensor HS, so that the dimension of thedriving mechanism 1 along the Z axis can be reduced to facilitateminiaturization of the mechanism.

Although embodiments of the present disclosure and their advantages havebeen described in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the disclosure as defined by the appendedclaims. For example, it will be readily understood by those skilled inthe art that many of the features, functions, processes, and materialsdescribed herein may be varied while remaining within the scope of thepresent disclosure. Moreover, the scope of the present application isnot intended to be limited to the particular embodiments of the process,machine, manufacture, composition of matter, means, methods and stepsdescribed in the specification. As one of ordinary skill in the art willreadily appreciate from the disclosure of the present disclosure,processes, machines, manufacture, compositions of matter, means,methods, or steps, presently existing or later to be developed, thatperform substantially the same function or achieve substantially thesame result as the corresponding embodiments described herein may beutilized according to the present disclosure. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.In addition, each claim constitutes a separate embodiment, and thecombination of various claims and embodiments are within the scope ofthe disclosure.

What is claimed is:
 1. A driving mechanism, comprising: a polygonal baseunit, including a substrate and a circuit board disposed on thesubstrate; a holder, movably connected to the base unit, wherein theholder is configured to hold an optical element that defines an opticalaxis; a first driving assembly, configured to drive the holder to moverelative to the base unit; a sensing magnet, disposed on the holder; anda magnetic field sensor, configured to detect the sensing magnet,wherein the magnetic field sensor is accommodated in a recess of thesubstrate.
 2. The driving mechanism as claimed in claim 1, wherein theholder forms a cavity for receiving the sensing magnet.
 3. The drivingmechanism as claimed in claim 2, wherein when viewed in a directionparallel to the optical axis, the recess of the substrate and the cavityof the holder at least partially overlap.
 4. The driving mechanism asclaimed in claim 1, wherein the circuit board is electrically connectedto the substrate.
 5. The driving mechanism as claimed in claim 1,wherein the magnetic field sensor is electrically connected to thecircuit board.
 6. The driving mechanism as claimed in claim 1, whereinthe substrate has an opening and a first pad exposed to an inner surfaceof the opening and electrically connected to the circuit board.
 7. Thedriving mechanism as claimed in claim 1, wherein the magnetic fieldsensor is configured to detect the movement of the holder relative tothe base unit in a direction parallel to the optical axis.
 8. Thedriving mechanism as claimed in claim 1, wherein when viewed in adirection parallel to the optical axis of the optical element, therecess of the substrate and the holder at least partially overlap. 9.The driving mechanism as claimed in claim 1, wherein the substrate hasan upper surface and a lower surface perpendicular to the optical axis,and the circuit board is disposed on the upper surface of the substrate.10. The driving mechanism as claimed in claim 1, wherein when viewed ina direction parallel to the optical axis of the optical element, theholder and the circuit board at least partially overlap.
 11. The drivingmechanism as claimed in claim 1, wherein when viewed along the opticalaxis of the optical element, the sensing magnet has a round, square, orrectangular shape.
 12. The driving mechanism as claimed in claim 1,further comprising a frame connected to the base unit, and the holder isreceived in the frame.
 13. The driving mechanism as claimed in claim 12,wherein when viewed along the optical axis of the optical element, theframe and the circuit board at least partially overlap.
 14. The drivingmechanism as claimed in claim 1, wherein the substrate has a conductivepin electrically connected to the magnetic field sensor.
 15. The drivingmechanism as claimed in claim 14, wherein the conductive pin and themagnetic field sensor are situated on opposite sides of the substrate.16. The driving mechanism as claimed in claim 1, further comprising aframe movably connected to the base unit, and the holder is received inthe frame, wherein the first driving assembly includes a magneticelement disposed on the frame and a coil disposed on the circuit board.17. The driving mechanism as claimed in claim 1, wherein the substratefurther has an opening, a group of first pads adjacent to each other,and a group of second pads adjacent to each other, wherein the first andsecond pads are exposed to an inner surface of the opening andelectrically connected to the circuit board.
 18. The driving mechanismas claimed in claim 17, wherein the first and second pads are located onopposite sides of the opening.
 19. The driving mechanism as claimed inclaim 1, wherein the first driving assembly is located close to a firstside of the base unit, and the sensing magnet is located close to asecond side of the base unit, opposite to the first side.
 20. Thedriving mechanism as claimed in claim 1, wherein the center of themagnetic field sensor is offset from the center of the sensing magnetalong a direction perpendicular to the optical axis.